Synthesis前兆群体异常信息提取与地震短期预测研究

Extraction of Anomaly Information of Synthesis Precursory Group and Study of Earthquake Short-term Forecast

建立了Synthesis法前兆群体异常信息提取的数学模型。选取滇东地区 1995～ 2 0 0 0年 9月间常用的 2 0项前兆资料 ,研究中强地震前后Synthesis法前兆群体异常的变化特征。研究结果表明 ,在研究时段内 ,Synthesis法前兆群体异常占时率为 0 15 8,为小概率事件。地震对应率为 5 / 6 =0 83 ,虚报率为 1/ 6 =0 17,地震均是在异常结束后 3个月之内发生 ,是对应概率很高的短期预报指标。成组异常出现均有成组地震对应 ,群体前兆“组异常”特征显著。处于计算前兆观测点中心的澄江地震前 ,异常幅度突出 ,预示了Synthesis值计算有利于提取近源短期异常。实际检验了Synthesis法在地震短期预报中的预报意义 ,获得了满意的效果。

A mathematical model for extracting the anomaly information of synthesis precursory group is set up. The often-used 20 items of precursory data from 1995 to September 2000 were selected to study the variation characteristics of synthesis precursory group before and after the mid-strong earthquakes. The results show that during the study period, the time to taking ratio of synthesis precursory group is 0.158, which is a small probability event. The corresponding ratio of earthquake is 5/6=0.83 and false alarm is 1/6=0.17. All the earthquakes happened within 3 months after the ending of the anomaly, which was a short-term prediction index with high corresponding probability. The grouped anomaly appeared corresponds to grouped earthquakes. The grouped anomaly of swarm precursors has significant feature. The precursory observation center had obvious anomaly before Chengjiangearthquake, which indicated that the synthesis value computation was propitious to extract short-term near field precursor. The practice has checked the prediction sense of synthesis in short-term earthquake prediction, and obtained satisffing effect.